Shannon, first I would say that practice makes perfect! Or at least, practice makes less panicky. I had a rough time my first tri last year, even though I am a pretty strong swimmer. I just wasn't used to not being able to see in the water.
I did a few practices and it's gotten better, so I think putting the yards in the ow is just as, or more beneficial than your pool laps.
How is your sighting? In an ow swim I will try to establish a pattern to my sighting that fits in with my pattern for breathing. Establishing a pattern helps me focus on the pattern instead of my mind dwelling on the unknown that could lurk beneath me.
I breath every 3 strokes, so bilaterally. I am a stronger sighter on my right-side (I can sight on the left, but it tires me more...I'm working on this), so right before I would rotate my head to breath right, I lift my head slightly so that my eyes are just above the water. Depending on chop I may have to lift it higher, but I try to minimize this so I don't get overly exhausted. After I look up quickly, I breathe to my right.
Part of my problem in my first swim was not pacing myself, too. I went out too fast, and my heartrate went to hell and I couldn't control my breathing. Start slow. If it makes you feel better, start at the back of the pack. If you're prone to panic, I feel that starting slow and building speed as I grow more comfortable helps me calm down.
When I swim in ow now I like to focus on something that makes me happy and calm, like the pretty reflections of the light through the hazy/murky water. It has such a neat quality, that I can't help but getting hypnotized by it and all thoughts of heeby jeebys leave my head.
But don't worry about having to resort to another stroke to quell the panic, many people do that. As you get more used to swimming in the open water, you'll realize that it's all a head game.
Good luck! Oh, and it won't hurt if you add some drills into your regular 1200 swims, like swimming a lap with your eyes closed (under water) and sighting on the blocks at the end as you breath, doing some tarzan drills (head up above water), and getting some good friends all in one lane with you and swimming en masse to the other end to simulate the dishwasher effect.
Edited to say that my coach has us doing some weird drills that seemed kinda cool though, by putting a few layers of saran wrap over our goggles on the inside so that everything was fuzzy an unclear. That might help too.
K.